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Search for "iminostilbene" in Full Text gives 3 result(s) in Beilstein Journal of Organic Chemistry.
Synthesis of heterocycles based on azomethine ylides from α-amino acids (or amines) and carbonyl compounds
- Ekaterina V. Berezhnaya,
- Alexander I. Ponyaev,
- Vitali M. Boitsov and
- Alexander V. Stepakov
Beilstein J. Org. Chem. 2026, 22, 705–741, doi:10.3762/bjoc.22.55
- cyclic olefins have shown good performance, in particular derivatives of cyclopentene, cyclooctene, norbornene, norbornanediene, indene, and iminostilbene. In turn, unsymmetrical imines containing aryl, heteroaryl π-deficient (pyrazine) or π-excessive (furan, thiophene, thiazole) substituents can also
Graphical Abstract
Scheme 1: Strategies for the preparation of pyrrolidine derivatives by (3 + 2) cycloaddition of azomethine yl...
Scheme 2: (3 + 2) Cycloaddition of iminoesters to dimethylmaleate.
Scheme 3: Cycloaddition of 1 with various dipolarophiles catalyzed by Ag(I)-L1.
Scheme 4: Cycloaddition of 1 with tert-butyl acrylate catalyzed by Ag(I)-L2.
Scheme 5: Cycloaddition of 1 with dimethyl maleate catalyzed by Cu(I)-L3.
Scheme 6: Cycloaddition of 1 with alkenes catalyzed by Zn(II)-t-Bu-BOX (L4).
Scheme 7: (3 + 2) Cycloaddition of iminoesters to acrylates.
Scheme 8: Catalytic double (3 + 2) cycloaddition to form pyrrolizidine derivatives.
Scheme 9: (3 + 2) Cycloaddition of iminoethers to vinyl phenyl sulfone.
Scheme 10: Regiodivergent and enantioselective synthesis of pyrrolidines 16 and 17.
Scheme 11: Substrate-controlled regioreversible "normal" and "incomplete" 1,3-dipolar cycloaddition.
Scheme 12: Enantioselective synthesis of exo-/endo-pyrrolidines.
Scheme 13: (3 + 2) Cycloaddition of iminoethers 21 to dipolarophiles 22–24.
Scheme 14: Synthesis of bicyclic pyrrolidines 29 from cyclopentene-1,3-diones.
Scheme 15: (3 + 2) Cycloaddition of aldimine esters and allyl alcohols using copper-ruthenium catalysis.
Scheme 16: Synthesis of 3,3-difluoro- and 3,3,4-trifluoropyrrolidine derivatives.
Scheme 17: Use of iminoesters from natural compounds and pharmaceuticals for reactions with 1,1-difluoro- and ...
Scheme 18: Reaction of iminoesters with 1,3-enynes.
Scheme 19: Synthesis of pyrrolidines from iminoesters and vinyl(hetero)arenes.
Scheme 20: Synthesis of exo-pyrrolidines 42 and 43.
Scheme 21: Enantioselective synthesis of heteroarylpyrrolidines 45 and 46.
Scheme 22: Catalytic reaction of (3 + 2) cycloaddition of imines 12 to benzofulvenes 47.
Scheme 23: Fullerene as a dipolarophile in (3 + 2) cycloaddition reactions.
Scheme 24: Asymmetric synthesis of optically active tetrasubstituted pyrrolidines 54.
Scheme 25: (3 + 2) Cycloaddition reaction of imines 55 and α,β-unsaturated aldehydes.
Scheme 26: Probable mechanism of enantioselective (3 + 2) cycloaddition of azomethine ylides to α,β-unsaturate...
Scheme 27: Cycloaddition between iminoesters 12 and sulfinylimines 58.
Scheme 28: (3 + 2) Cycloaddition between triarylideneacetylacetone and azomethine ylides in the presence of ti...
Scheme 29: Stereoselective synthesis of decahydropyrrolo[2,1,5-cd]indolizine 66.
Scheme 30: Synthesis of policyclic derivatives 71 and 72.
Scheme 31: Catalytic аsymmetric (3 + 2) сycloaddition of 2-pyridylimines with N-methylmaleimide.
Scheme 32: Catalytic аsymmetric (3 + 2) сycloaddition of 2-pyridylimines 1 with other dipolarophiles.
Scheme 33: Enantioselective (3 + 2) cycloaddition of silylimine with various dipolarophiles.
Scheme 34: Proposed mechanism of formation of pyrrolidines 78.
Scheme 35: Synthesis of polyheterocyclic pyrrolidines 82–91.
Scheme 36: Synthesis of spirocyclic (95) and fused (96) pyrrolidines.
Scheme 37: (3 + 2) Cycloaddition involving aromatic aldehydes 97, N-propargylmaleimide (98) and α-amino acids ...
Scheme 38: Synthesis of pyrrolizidines 106 and by-product 107.
Scheme 39: Iridium-catalyzed three-component cascade (3 + 2) cycloaddition.
Scheme 40: Intramolecular (3 + 2) cycloaddition of N-alkenylpyrrole-2-carbaldehyde 110 and α-amino acids.
Scheme 41: Three-component (3 + 2) cycloaddition involving fullerene.
Scheme 42: Four-component stereoselective one-pot synthesis of spiro-cycloadducts 119–122.
Scheme 43: Reactions of azomethine ylide 123 with cyclopropenes.
Scheme 44: Three-component reactions involving ninhydrin, cyclopropenes and acyclic α-amino acids.
Scheme 45: Reaction of cyclopropenes 138 with the N-protonated form of Ruhemann purple 137.
Scheme 46: Enantioselective (3 + 2) cycloaddition of azomethine ylides generated in situ from isatins and amin...
Scheme 47: (3 + 2) Cycloaddition of cyclohexenone 143, isatins 140 and aminomalonic diesters 141, catalyzed by...
Scheme 48: Enantioselective (3 + 2) cycloaddition of azomethine ylides generated in situ from isatins and amin...
Scheme 49: Enantioselective (3 + 2) cycloaddition of azomethine ylides generated in situ from isatins and benz...
Scheme 50: (3 + 2) Cycloaddition involving isatins, azetidine-2-carboxylic acid, maleimides or itaconimides.
Scheme 51: (3 + 2) Cycloaddition involving isatins, amino acids and tetraethylvinylidenebis(phosphonate).
Scheme 52: Synthesis of spirooxindoles 156 from triarylideneacetylacetones 155.
Scheme 53: Synthesis of spirooxindole derivatives 157–160.
Scheme 54: Synthesis of hybrid spiro-heterocycles 164–166.
Scheme 55: Formation of azomethine ylide from isatin and sarcosine.
Scheme 56: (3 + 2) Cycloaddition involving isatins, amino acids and trans-3-benzoylacrylic acid.
Scheme 57: Regioselective synthesis of spirooxindoles 170.
Scheme 58: Synthesis of hybrid spiro-heterocycles 86.
Scheme 59: (3 + 2) Cycloaddition involving acenaphthenequinones, amino acids and cyclopropenes.
Scheme 60: Synthesis of hybrid glyco-3-nitrochromane cycloadducts 179.
Scheme 61: Synthesis of spiro[indenoquinoxaline-(thia)pyrrolizidines] 90a.
Scheme 62: Three-component reactions of cyclopropenes, 11H-indeno[1,2-b]quinoxalin-11-onesand α-amino acids, s...
Scheme 63: Synthesis of hybrid glyco-3-nitrochromane cycloadducts 92.
Scheme 64: (3 + 2) Cycloaddition of 11H-benzo[4,5]imidazo[1,2-a]indol-11-one (189) with cyclopropenes and male...
Scheme 65: Diastereoselective synthesis of spiro derivatives of barbituric acid from alloxan 193, α-amino acid...
Scheme 66: Probable mechanism of formation of azomethine ylide from alloxan and ʟ-proline.
Scheme 67: Three-component reactions involving tryptanthrin 196, α-amino acids and cyclopropenes.
Synthesis and applications of alkenyl chlorides (vinyl chlorides): a review
- Daniel S. Müller
Beilstein J. Org. Chem. 2026, 22, 1–63, doi:10.3762/bjoc.22.1
Graphical Abstract
Figure 1: Representative alkenyl chloride motifs in natural products. References: Pinnaic acid [8], haterumalide ...
Figure 2: Representative alkenyl chloride motifs in pharmaceuticals and pesticides. References: clomifene [25], e...
Figure 3: Graphical overview of previously published reviews addressing the synthesis of alkenyl chlorides.
Figure 4: Classification of synthetic approaches to alkenyl chlorides.
Scheme 1: Early works by Friedel, Henry, and Favorsky.
Scheme 2: Product distribution obtained by H NMR integration of crude compound as observed by Kagan and co-wo...
Scheme 3: Side reactions observed for the reaction of 14 with PCl5.
Scheme 4: Only compounds 15 and 18 were observed in the presence of Hünig’s base.
Scheme 5: Efficient synthesis of dichloride 15 at low temperatures.
Scheme 6: Various syntheses of alkenyl chlorides on larger scale.
Scheme 7: Scope of the reaction of ketones with PCl5 in boiling cyclohexane.
Scheme 8: Side reactions occur when using excess amounts of PCl5.
Scheme 9: Formation of versatile β-chlorovinyl ketones.
Scheme 10: Mixture of PCl5 and PCl3 used for the synthesis of 49.
Scheme 11: Catechol–PCl3 reagents for the synthesis of alkenyl chlorides.
Scheme 12: (PhO)3P–halogen-based reagents for the synthesis of alkenyl halides.
Scheme 13: Preparation of alkenyl chlorides from alkenyl phosphates.
Scheme 14: Preparation of alkenyl chlorides by treatment of ketones with the Vilsmeier reagent.
Scheme 15: Preparation of electron-rich alkenyl chlorides by treatment of ketones with the Vilsmeier reagent.
Scheme 16: Cu-promoted synthesis of alkenyl chlorides from ketones and POCl3.
Figure 5: GC yield of 9 depending on time and reaction temperature.
Figure 6: Broken reaction flask after attempts to clean the polymerized residue.
Figure 7: GC yield of 9 depending on the amount of CuCl and time.
Scheme 17: Treatment of 4-chromanones with PCl3.
Scheme 18: Synthesis of alkenyl chlorides from the reaction of ketones with acyl chlorides.
Scheme 19: ZnCl2-promoted alkenyl chloride synthesis.
Scheme 20: Regeneration of acid chlorides by triphosgene.
Scheme 21: Alkenyl chlorides from ketones and triphosgene.
Scheme 22: Various substitution reactions.
Scheme 23: Vinylic Finkelstein reactions reported by Evano and co-workers.
Scheme 24: Challenge of selective monohydrochlorination of alkynes.
Scheme 25: Sterically encumbered internal alkynes furnish the hydrochlorination products in high yield.
Scheme 26: Recent work by Kropp with HCl absorbed on alumina.
Scheme 27: High selectivities for monhydrochlorination with nitromethane/acetic acid as solvent.
Figure 8: Functionalized alkynes which typically afford the monhydrochlorinated products.
Scheme 28: Related chorosulfonylation and chloroamination reactions.
Scheme 29: Reaction of organometallic reagents with chlorine electrophiles.
Scheme 30: Elimination reactions of dichlorides to furnish alkenyl chlorides.
Scheme 31: Elimination reactions of allyl chloride 182 to furnish alkenyl chloride 183.
Scheme 32: Detailed studies by Schlosser on the elimination of dichloro compounds.
Scheme 33: Stereoselective variation caused by change of solvent.
Scheme 34: Elimination of gem-dichloride 189 to afford alkene 190.
Scheme 35: Oxidation of enones to dichlorides and in situ elimination thereof.
Scheme 36: Oxidation of allylic alcohols to dichlorides and in situ elimination thereof.
Scheme 37: Chlorination of styrenes with SOCl2 and elimination thereof.
Scheme 38: Chlorination of styrenes with SOCl2 and elimination thereof.
Scheme 39: Fluorine–chlorine exchange followed by elimination.
Scheme 40: Intercepting cations with alkynes and trapping of the alkenyl cation intermediate with chloride.
Scheme 41: Investigations by Mayr and co-workers.
Scheme 42: In situ activation of benzyl alcohol 230 with BCl3.
Scheme 43: In situ activation of benzylic alcohols with TiCl4.
Scheme 44: In situ activation of benzylic alcohols with FeCl3.
Scheme 45: In situ activation of benzylic alcohols with FeCl3.
Scheme 46: In situ activation of aliphatic chlorides and alcohols with ZnCl2, InCl3, and FeCl3.
Scheme 47: In situ generation of benzylic cations and trapping thereof with alkynes.
Scheme 48: Intramolecular trapping reactions affording alkenyl halides.
Scheme 49: Intramolecular trapping reactions affording alkenyl chlorides.
Scheme 50: Intramolecular trapping reactions of oxonium and iminium ions affording alkenyl chlorides.
Scheme 51: Palladium and nickel-catalyzed coupling reactions to afford alkenyl chlorides.
Scheme 52: Rhodium-catalyzed couplings of 1,2-trans-dichloroethene with arylboronic esters.
Scheme 53: First report on monoselective coupling reactions for 1,1-dichloroalkenes.
Scheme 54: Negishi’s and Barluenga’s contributions.
Scheme 55: First mechanistic investigation by Johnson and co-workers.
Scheme 56: First successful cross-metathesis with choroalkene 260.
Scheme 57: Subsequent studies by Johnson.
Scheme 58: Hoveyda and Schrock’s work on stereoretentive cross-metathesis with molybdenum-based catalysts.
Scheme 59: Related work with (Z)-dichloroethene.
Scheme 60: Further ligand refinement and traceless protection of functional groups with HBpin.
Scheme 61: Alkenyl chloride synthesis by Wittig reaction.
Scheme 62: Alkenyl chloride synthesis by Julia olefination.
Scheme 63: Alkenyl chloride synthesis by reaction of ketones with Mg/TiCl4 mixture.
Scheme 64: Frequently used allylic substitution reactions which lead to alkenyl chlorides.
Scheme 65: Enantioselective allylic substitutions.
Scheme 66: Synthesis of alkenyl chlorides bearing an electron-withdrawing group.
Scheme 67: Synthesis of α-nitroalkenyl chlorides from aldehydes.
Scheme 68: Synthesis of alkenyl chlorides via elimination of an in situ generated geminal dihalide.
Scheme 69: Carbenoid approach reported by Pace.
Scheme 70: Carbenoid approach reported by Pace.
Scheme 71: Ring opening of cyclopropenes in the presence of MgCl2.
Scheme 72: Electrophilic chlorination of alkenyl MIDA boronates to Z- or E-alkenyl chlorides.
Scheme 73: Hydroalumination and hydroboration of alkynyl chlorides.
Scheme 74: Carbolithiation of chloroalkynes.
Scheme 75: Chlorination of enamine 420.
Scheme 76: Alkyne synthesis by elimination of alkenyl chlorides.
Scheme 77: Reductive lithiation of akenyl chlorides.
Scheme 78: Reactions of alkenyl chlorides with organolithium reagents.
Scheme 79: Reactions of alkenyl chlorides with organolithium reagents.
Scheme 80: Addition–elimination reaction of alkenyl chloride 9 with organolithium reagents.
Scheme 81: C–H insertions of lithiumcarbenoids.
Scheme 82: Pd-catalyzed coupling reactions with alkenyl chlorides as coupling partner.
Scheme 83: Ni-catalyzed coupling of alkenylcopper reagent with alkenyl chloride 183.
Scheme 84: Ni-catalyzed coupling of heterocycle 472 with alkenyl chloride 473.
Scheme 85: Synthesis of α-chloroketones by oxidation of alkenyl chlorides.
Scheme 86: Tetrahalogenoferrate(III)-promoted oxidation of alkenyl chlorides.
Scheme 87: Chlorine–deuterium exchange promoted by a palladium catalyst.
Scheme 88: Reaction of alkenyl chlorides with thiols in the presence of AIBN (azobisisobutyronitrile).
Scheme 89: Chloroalkene annulation.
Strategies in the synthesis of dibenzo[b,f]heteropines
- David I. H. Maier,
- Barend C. B. Bezuidenhoudt and
- Charlene Marais
Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51
- frameworks with dibenzo[b,f]azepine derived ligands have also been reported. This review provides a brief overview of the different synthetic strategies to dibenzo[b,f]azepines and other dibenzo[b,f]heteropines. Keywords: dibenzo[b,f]azepine; dibenzo[b,f]heteropine; dibenzo[b,f]oxepine; iminostilbene
- to 5H-dibenzo[b,f]azepine (1a) 10,11-Dihydro-5H-dibenzo[b,f]azepine (2a), also known as iminobibenzyl (2a), is used as precursor for several compounds, including 5H-dibenzo[b,f]azepine (iminostilbene) (1a), and therefore will be discussed in a section on large scale industrial synthesis. While
- ) by alkylation of 1a was patented in 1997 [79]. The process involves the alkylation of iminostilbene (1a) as a critical intermediate step (Scheme 33C). The alkyl halide linker of 148 was further functionalised by reaction with piperazine derivative 149 to give opipramol (5). 6.2 C-Functionalisation
Graphical Abstract
Figure 1: Dibenzo[b,f]azepine (1a), -oxepine (1b) and -thiepine (1c) as examples of dibenzo[b,f]heteropines (1...
Figure 2: Selected pharmaceuticals with the dibenzo[b,f]azepine skeleton.
Figure 3: Examples of 10,11-dihydrodibenzo[b,f]azepine-based ligands.
Figure 4: The dibenzo[b,f]azepine moiety in dyes with properties suitable for the use in organic light emitti...
Figure 5: Selective bioactive natural products (13–18) containing the dibenzo[b,f]oxepine scaffold and Novart...
Scheme 1: Retrosynthetic approach to 5H-dibenzo[b,f]azepine (1a) from nitrotoluene (22).
Scheme 2: Oxidative coupling of o-nitrotoluene (22) and reduction of 2,2'-dinitrobibenzyl (21) to form 2,2'-d...
Scheme 3: Synthesis of 10,11-dihydro-5H-dibenzo[b,f]azepine (2a) via amine condensation.
Scheme 4: Catalytic reduction of 10,11-dihydro-5H-dibenzo[b,f]azepine (2a).
Scheme 5: The Wagner–Meerwein rearrangement of acridin-9-ylmethanol (23) into 5H-dibenzo[b,f]azepine (1a).
Scheme 6: Oxidative ring expansion of 2-(9-xanthenyl)malonates 24.
Scheme 7: Ring expansion via C–H functionalisation.
Scheme 8: The synthesis of fluorinated 5H-dibenzo[b,f]azepine 38 from isatin (32).
Scheme 9: The synthesis of substituted dibenzo[b,f]azepines 43 from indoles 39.
Scheme 10: Retrosynthetic pathways to dibenzo[b,f]azepines via Buchwald–Hartwig amination.
Scheme 11: Synthesis of dibenzo[b,f]oxepine 54 and -azepine 55 derivatives via (i) Heck reaction and (ii) Buch...
Scheme 12: Double Buchwald–Hartwig amination and thioetherification in the synthesis of tricyclic azepines 60 ...
Scheme 13: Double Buchwald–Hartwig amination towards substituted dibenzoazepines 62.
Scheme 14: Double Buchwald–Hartwig amination towards 10,11-dihydro-5H-dibenzo[b,f]azepine derivatives 71.
Scheme 15: One-pot Suzuki coupling–Buchwald–Hartwig amination.
Scheme 16: One-pot Rh/Pd-catalysed synthesis of dihydropyridobenzazepines.
Scheme 17: A retrosynthetic pathway to dibenzo[b,f]azepines via Mizoroki–Heck reaction.
Scheme 18: One-pot domino Pd-catalyzed Mizoroki–Heck–Buchwald–Hartwig synthesis of dibenzo[b,f]azepines.
Scheme 19: Dibenzo[b,f]thiapine and -oxepine synthesis via SNAr (thio)etherification, Wittig methylenation and...
Scheme 20: A retrosynthetic pathway to dibenzo[b,f]oxepines via Ullmann coupling.
Scheme 21: Ullmann-type coupling in dibenzo[b,f]oxepine synthesis.
Scheme 22: Wittig reaction and Ullmann coupling as key steps in dihydrobenz[b,f]oxepine synthesis.
Scheme 23: Pd-catalysed dibenzo[b,f]azepine synthesis via norbornene azepine intermediate 109.
Scheme 24: A simple representation of olefin metathesis resulting in transalkylidenation.
Scheme 25: Ring-closing metathesis as key step in the synthesis of dibenzo[b,f]heteropines.
Scheme 26: Alkyne–aldehyde metathesis in the synthesis of dibenzo[b,f]heteropines.
Scheme 27: Hydroarylation of 9-(2-alkynylphenyl)-9H-carbazole derivatives.
Scheme 28: Oxidative coupling of bisphonium ylide intermediate to give pacharin (13).
Scheme 29: Preparation of 10,11-dihydrodibenzo[b,f]heteropines via intramolecular Wurtz reaction.
Scheme 30: Phenol deprotonation and intramolecular etherification in the synthesis of bauhinoxepine J.
Figure 6: Functionalisation of dibenzo[b,f]azepine.
Scheme 31: Palladium-catalysed N-arylation of dibenzo[b,f]azepine.
Scheme 32: Cu- and Ni-catalysed N-arylation.
Scheme 33: N-Alkylation of dibenzo[b,f]azepine (1a) and dihydrodibenzo[b,f]azepine (2a).
Scheme 34: Preparation of methoxyiminosilbene.
Scheme 35: Synthesis of oxcarbazepine (153) from methoxy iminostilbene 151.
Scheme 36: Ring functionalisation of dihydrodibenzo[b,f]azepine.
